Abstract

As an innovative way of Enhancing Oil Recovery (EOR), the air foam flooding technique comprises the merits of air flooding and foam flooding, which not only has the double effects on profile controlling and oil displacement, but also avoids the gas channeling weakness. In the present work, the air foam flooding seepage flow mechanics is studied. Based on the similarity principle, the sand pack core samples for both air flooding and air foam flooding were elaborately designed and prepared to prove the reliability of the inherent mechanism of the air foam flooding. The results show that the increase of gas phase viscosity and the decrease of gas phase permeability make the gas phase mobility with foam far smaller than the one without foam. The decrease of the mobility ratio between gas-crude oil and gas-formation water helps to eliminate the viscous fingering and gas channeling, which enhances the gas displacement efficiency. The blocking ability and the profile controlling of the foam can significantly prolong the gas breakthrough period. Since oxygen concentration fell sharply during the gas breakthrough, it can effectively reduce the potential hazard in the process of air injection